[x3d-public] Units for BVH vs HAnimMotion.values

Sat Oct 14 17:08:03 PDT 2023

I don’t have an original BVH file, but converted, so I’m not sure where the
issue is.  I recall having success with X3D-Edit BVH import though.  AFAIK,
X3D-Edit does not solve the joint/bone mapping problem from BVH to HAnim?
Let me know.  That’s why I bailed on BVH.  Doug is working on that.

On Sat, Oct 14, 2023 at 2:34 PM Brutzman, Donald (Don) (CIV) <
brutzman at nps.edu> wrote:

> Wondering if you are reporting issues to Blender, John.
>
>
>
> We found when writing the BVH import for X3D-edit that not all BVH files
> are formatted exactly the same, it was never standardized.
>
>
>
>    - X3D-Edit 4.0 Authoring Tool for Extensible 3D (X3D) Graphics
>    - https://savage.nps.edu/X3D-Edit
>    - X3D-Edit is a free, open-source Extensible 3D (X3D) Graphics
>    authoring tool for simple high-quality authoring, editing, import/export,
>    validation and viewing of X3D scenes.
>    - Suggested installation: install Apache NetBeans first, then install
>    the X3D-Edit plugin.  Most reliable, you also will get notifications of
>    updates automatically.
>
>
>
> If you have a working BVH example that X3D-Edit has trouble handling and
> importing, then I’ll be happy to add corrections for that to our TODO
> list.  Thanks for all efforts.
>
>
>
> all the best, Don
>
> --
>
> Don Brutzman  Naval Postgraduate School, Code USW/Br
> brutzman at nps.edu
>
> Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA
> +1.831.656.2149
>
> X3D graphics, virtual worlds, navy robotics
> https://faculty.nps.edu/brutzman
>
>
>
> *From:* x3d-public <x3d-public-bounces at web3d.org> *On Behalf Of *Joe D
> Williams
> *Sent:* Saturday, October 14, 2023 12:27 PM
> *To:* John Carlson <yottzumm at gmail.com>; GPU Group <gpugroup at gmail.com>
> *Cc:* x3d-public at web3d.org
> *Subject:* Re: [x3d-public] Units for BVH vs HAnimMotion.values
>
>
>
> > I’ve not had success with Blender Bvh import.
>
>
>
> Success with blender would mean you have a blender skeleton that is
> animated by the bvh euler angle rotation data.
>
>
>
> Don't even bother with Blender, maybe, because x3d does a documented
> conversion and the order of success is the same. The skeleton animated
> using the motion node directly may or may not actually convert to use
> interpolators. Or, the angle data is fully converted as shown to x3d syntax
> interpolator-driven animations used to control the skeleton. Just because
> the x3d player can use the bvh motion file doesn't mean it has to expose
> any x3d syntax.
>
>
>
> > is sufficient to imply Motion data is in degrees? Thee is no spec for
> bvh. Per part 2, if you have a file that looks like the descriptions, has
> the sample set of keywords and data structures, then give it a go. We also
> show how actually convert the file to x3d syntax if it is worth examining
> in detail.
>
>
>
> Joe
>
>
>
>
>
> -----Original Message-----
> From: John Carlson <yottzumm at gmail.com>
> Sent: Oct 14, 2023 8:00 AM
> To: GPU Group <gpugroup at gmail.com>
> Cc: Joe D Williams <joedwil at earthlink.net>, <x3d-public at web3d.org>
> Subject: Re: [x3d-public] Units for BVH vs HAnimMotion.values
>
>
>
> I’ve not had success with Blender Bvh import.
>
>
>
> John
>
>
>
> On Sat, Oct 14, 2023 at 6:54 AM GPU Group <gpugroup at gmail.com> wrote:
>
> The Blender > Export/Import > mocap bvh code may have some hints.
>
> Hypothesis: on import it converts from mocap to interpolators, on export
> goes the other way.
>
>
>
> Q. do you think that HAnim 5.2.4 Angle Conversion Procedure is sufficient
> to imply Motion data is in degrees? It doesn't mention the Motion node
> explicitly (Hypothesis written in an early era).. If so we could make the
> Motion.values degrees by default, as Joe suggested and 5.2.4 'indirectly
> implies'?
>
> -Doug
>
>
>
>
>
>
>
> On Sat, Oct 14, 2023 at 2:47 AM John Carlson <yottzumm at gmail.com> wrote:
>
>
>
> Here's the Euler Angle to Axis-Angle in HAnim Pt section 5.2.4
>
>
>
>
> https://www.web3d.org/documents/specifications/19774/V2.0/MotionDataAnimation/AnimationUsingInterpolators.html#AngleConversionProcedure
>
>
>
> Hmm!  I'm guessing that Blender has a routine for this! Sure enough!
> Trying it now.
>
>
>
> Not with HAnimMotion, I don't know how to do that yet.  Suggestions?
>
>
>
> John
>
>
>
> On Sat, Oct 14, 2023 at 12:21 AM Joe D Williams <joedwil at earthlink.net>
> wrote:
>
> > Um, then why is angle even listed here?
>
>
>
> That is easy, take another look.
>
> Euler angles are not listed anywhere!
>
> Convert to axis-angle like showed in Part 2 and forget xyz angles/
>
> Joe
>
>
>
>
>
> -----Original Message-----
> From: John Carlson <yottzumm at gmail.com>
> Sent: Oct 13, 2023 6:15 PM
> To: Joe D Williams <joedwil at earthlink.net>
> Cc: <x3d-public at web3d.org>
> Subject: Re: [x3d-public] Units for BVH vs HAnimMotion.values
>
>
>
> Um, then why is angle even listed here?
>
>
>
> Confusing as heck!
>
>
>
>
> https://www.web3d.org/documents/specifications/19775-1/V4.0/Part01/concepts.html#t-Standardunits
>
>
>
> John
>
>
>
>
>
> On Fri, Oct 13, 2023 at 7:19 PM Joe D Williams <joedwil at earthlink.net>
> wrote:
>
> > otherwise specified in a UNIT statement
>
>
>
>
> https://www.web3d.org/documents/specifications/19775-1/V4.0/Part01/concepts.html#Standardunitscoordinates
>
>
>
> "However, the world coordinate units may be modified by specifying a
> different length unit using the UNIT statement."
>
>
>
> There is Not Now nor will there Ever be a UNIT statement that allows
> degrees for rotation and orientation.
>
>
>
> Never, will angles appear in any x3d animation interpolator.
>
> To apply an import using angle units, it is converted to x3d before use,
> then discarded or possibly stored somewhere away from working area for
> reference.
>
>
>
> Thanks and Best,
>
> Joe
>
>
>
> -----Original Message-----
> From: John Carlson <yottzumm at gmail.com>
> Sent: Oct 13, 2023 11:44 AM
> To: X3D Graphics public mailing list <x3d-public at web3d.org>
> Subject: [x3d-public] Units for BVH vs HAnimMotion.values
>
>
>
> Apparently BVH uses degrees for rotations.  Units for HAnimMotion should
> use radians unless otherwise specified in a UNIT statement, AFAIK.
>
>
>
> Comments?
>
>
>
> Thanks!
>
>
>
> John
>
>
>
>
>
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